A number of medical problems involving the foot or lower leg may only be resolved or even maintained in a stable condition by ensuring that the sole of the foot is maintained on a flat or planar surface permitting little or no flexure of the foot. In particular, such medical problems as postoperative recuperation, diabetic ulcers and arthritis may require the sole of the foot to be maintained on a planar surface and unflexed.
In the past, footwear has been provided which maintains the sole of the foot on the planar surface of a rigid platform defining an inner sole. A planar outer sole is defined on the bottom side of the platform which contacts the ground or walking surface and is generally parallel to the inner sole contacting the foot. While maintaining the foot in the unflexed state and being adequate for a standing position, the rigidity and planar outer sole of the footwear inhibits the natural walking motion of the foot and lower leg. The natural motion or striding action of a normal foot in walking is a cycle where, typically, the heel of the foot first contacts the ground, with the weight of the body being shifted forward along the foot until it finally rests on the ball or metatarsal point of the foot with the heel raised off the walking surface to propel the body forward. This footwear provides no means to simulate this cycle. The wearer of such footwear is forced to either lift the foot completely from the ground to walk or slide his foot sideways, forcing the wearer to an unnatural and tiring manner of walking.
In addition, the footwear or shoes worn by a person having a normal and healthy foot also inhibits the natural motion and striding action of the wearer when walking. Most footwear is flexible so that the foot deforms the sole of the shoe in a manner that conforms with the flexure of the sole of the foot. However, shear stresses are developed between the interface of the skin of the foot and the interior of the shoe since the foot is somewhat mobile within the shoe. As the heel is lifted off the ground in the normal walking motion, the weight of the body is supported on the meta heads, causing prolonged localized areas of stress in the metatarsal region which tends to sensitize these areas. The necessity to flex the sole of the shoe requires energy input from the wearer and may result in fatigue or localized stress areas on the foot.
A need has thus arisen for a postoperative shoe permitting the wearer to walk with a natural motion while maintaining the foot unflexed. Additionally, a need has arisen for an orthopedic shoe which immobilizes the foot in the shoe while simulating the normal motion of walking to provide greater comfort and less energy expenditure.